Sun visors must maintain a sufficient retention force to overcome the weight of the sun visor blade or body and hold the sun visor against the headliner in the home or storage position. This is necessary in order to maintain the sun visor in place and prevent it from swinging down unintentionally from the home position. Less critically, a weak retention force also allows the visor to flutter when the vehicle shakes, creating an annoyance and a perceived lack of quality.
Current visor technology utilizes a leaf spring built into the visor support rod upon which the body is pivotally mounted to retain the sun visor in the home position. Such a construction is disclosed in, for example, U.S. Pat. No. 4,394,043 to Moulding et al. This strategy counters the weight of the visor body by applying a moment at the base of the visor body. Unfortunately, this method of retention generates significant bending stresses on the sun visor body forcing visor construction material and thickness selection.
The flaw with existing retention technology is that the retention forces are only applied at the rod. In cases where detention is the limiting factor on sun visor body stiffness applying a retention force at the end of the visor opposite the rod would enable thinner and lighter visor body construction. A further disadvantage to the existing technology is that the leaf spring retention mechanism is built for a specific angle at which the sun visor locks into detention so that it is held in the home position. Disadvantageously, a single vehicle program may need multiple sun visor retention spring designs to accommodate variations in headliner geometry which often varies, for example, from a standard roof vehicle to a vehicle incorporating a moon roof.
The sun visor that is the subject matter of this document incorporates a magnetic detention system so as to provide a retention force at the end of the sun visor body opposite the rod to thereby enable construction of the sun visor body from thinner and lighter materials. Further, the magnetic detention system is effective for maintaining a sun visor body in the home position over a wider range of geometries or configurations including for both standard roof and moon roof equipped vehicles.